Art of burning finely divided fuel



Nov. 26, 1929.. E. LUNDGRr-:N 1,736,929

ART OF BURNING FINELY DIVIDED FUEL Filed NOV. 19, 1924 Ill @HQ i ,UWE/WOR Bv v ATTORNEYS y Patented Nov. ze, 1929 Unirse STATES.' 'PArENT ori-rcs EDWIN LNDGREN, or FREDERICK, MARYLAND, AssrNoR ro ooMBUs'rroN ENGINEER v me ooRroRArroN, A. CORPORATION or vNnyv YORK h ART 01:" BURNING FINELY DIVIDED FUEL Application led November 19, 1924. Serial No. 750,723.

This invention relates to the generation o steam by the burning of finely divided fuel,

and is especially useful in stationary boilerlX 'v installations in which the fuel is in'the fornr` of pulverized coal.

011e of the primary objects ofmy invention f combustion chamber, having an outlet 6 in i the upper part thereof, over which therey is arranged a part of the boiler to be hereinafter described. The rear portion of the side walls of the combustion chamber are covered with 5- water walls 7 andthe bridge wall is covered is to increase the rate `of evaporation, enabling by a water wall 8,such water walls being comme to generate a given arnou`nt of steamwith posed of tubes preferably provided with fins a boiler of smaller size, or stated in other arranged to overlap. The water walls 7 and words, to enable me to develop more steam 18 cooperate'to denne aportion of the combusm,

from a boiler of standard size of given type.

i lAnother object of myA invention is for a given output or capacity to generally decrease the size and expense of boiler installations.

To obtain the desirediincrease vin capacity with relativesmallness of installation, l proose to define the combustion space of the urnace chamber very largely by the. heat absorbing surfaces of the boiler, so that the 'A20 latter will be subject to radiant heat and,

.ntherefore, perform at a vry high rate. A

With such an arrangement, however, by

reason of the great absorption of the heat absorbing surfaces, there will be a considera- 25 ble' chilling effect on the furnace temperature,

and l therefore propose to add heat, or rather introduce heat to the combustion space to lproperly support combustion.

. l further propose to obtain this additional w heat'by providing such a relationin regular operation, between the rate of fuel feed, the amount of heat absorbing surface and the time interval for the combustion of the fuel vin .the combustion space, as to obtain a 'temperature of the gases leavingthe combustion space suciently high to permit me to extract the required amount of heat for introduction to the combustion space.

How the foregoing, together with such other obiects, as may or are incident to my invention7 are realized, is illustrated in the preferred form in the accompanying drawings wherein;

lig. i is a vertical section thru an installaf tion embodying my improvements Fig. 2 illustrates one form of burner which may be` employed in carrying out my invention; v

lig. 3 illust-rates a modified form of burner.

5@ Referring now to Fig. l, A represents the hereinafter appear, v

ttionspace.

of the combustion chamber and the front wall 11 of such combustioncharnber are comfao posed of refractories and are not protected by heat'absorbing surfaces, in the preferred embodiment of my invention. l

Fuel is admitted in an upper part of the combustion chamber in a downward direc- *151 tion in the space defined by the refractories, thru the medium of 'a plurality of burner nozzles B, arranged in al row transversely of the chamber. The'fuel and flame stream takes a downward course and then reverts in U eformasthe downward' momentum is overcome. y

` The boiler over the outlet andin 'the odtake comprises the two spaced sections or..

- banks of tubes C and D., between'which are es l located the superheater elements E and air Y heater F the baming being such that the gases y take the course through the o'take and to the stack indicated by the arrows.

Air is supplied to the heater sists of a plurality of pipes or tubes (preferably treated to withstand high temperatures), by the pipe l2 and fan 13, and is conducted i therefrom by the pipe 14 tofa manifold l5 which is provided with outlet and discharge 'e5 casings 16, one around each nozzle.

/The coal is supplied to the burners, preferably with carrying air and the 'entering fuel streams are surrounded by the preheated air i supplied around the nozzles. zThispreheated10o F, which con4 no having an oftake for the productsy of conlbustion, boiler tubes in said ofl'take subject to the products ofcombustion, air heater means in the offtake adapted to supply preheated air to the burner means, and a stack for the waste gases, together with air pre'- heater means in the stack and means whereby preheated air therefrom is supplied to the combustion space.

In testimony signed my name. 1

EDIVIN LUNDGREN.

gases leave at a comparatively high telnperature, and carry suiicient heat for the abstraction of the necessary heat for return to -the combustion spaceythis with combustion completed in the combustion space. The air heater F, being located just beyond the first section of the upper pKartof the boiler, is subjected to the very hot gases and the air passing therethroughis heated to a high degree, from 400 to 700" or more. This hot air survrounding each entering fuel stream and mingling therewith by v1rtue of eddy1ng,ldue

to difference in velocity, the construction of the burners and the like, immediately inst-itutes ignition with the aid of the radiant heat from the refractories. It and the radiant heatand the hotl air admitted through the front wall expedite combustion and carry it well r`forward before the general fuel and llame stream turns into that portion( of the combustion space defined by the tubes, and the heat from the forward portion 'of the chamber and from the burning fuel therein maintains proper combustion throughout. the combustion space. Thus the chilling effect of the tubes is overcome. IVhile the gases leave at, a high temperature, the nal exit temperature is kept within allowable limits because of the further abstraction of heat in the stack.

By admission of air at right angles to the plane of fuel delivery eddying is set up ensuring proper admixture.

In case ditliculty is encountered with coking at the nozzles, the preheated air may be l supplied according to the arrangement of Fig. 3, in which the manifold l5a is provided with pairs of delivery channels 16, one on each side of the nozzles. By this arrangement, the nozzles are not heated to thesame degree, but nevertheless the fuel is inlinediately subjected to 4highly heated air and eddying is quickly instituted by the i1npingement of the hot air and the coal.

I claim:

In a. pulverized fuel burning boiler furnace, a combustion chamber having a sul stantial portion of its combustion space dened in partby non-metallic refractory walls and in part b v water containing walls, burner means for admitting the fuel in the region defined by the refractories, said vchamber whereof, I have hereunto 

